Clean and peel the chestnuts. Melt the butter in a pot and sauté the chestnuts, leeks, and potatoes.
Pour in the beer, let it evaporate, add broth to cover by 1 inch, and continue cooking.
Pass the mixture through a food mill, reheat, and whisk in the cream and egg yolks. Heat, stirring until thickened, but do not let the mixture boil. Serve with bread.
